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Sound Power Measurement in a Semi-Reverberant, Volume Deficient Chamber
Technical Paper
2015-01-2359
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
Sound power can be determined using a variety of methods, but precision methods require the volume of the noise source to be less than 1% of the chamber volume leading to relatively large test chambers. Automotive torque converter performance and noise testing is completed in an enclosed metallic test fixture which inhibits the use of precision methods due to volume and space limitations. This paper describes a new method developed to accurately determine sound power of an automotive torque converter in a relatively small enclosure through characterization of the test environment. The test environment was characterized using two reference noise sources designed to represent torque converter noise output and physical geometry. Sound pressure levels of the sources were measured at multiple microphone locations and at three source amplitude levels to characterize the environment. Test results were analyzed statistically to determine the microphone positions that best represent the overall sound levels in the chamber. Optimum measurement positions were found to depend on source size but independent of source amplitude. Accuracy was determined based on the variance between the sound pressure levels at each microphone position. Sound power correction factors were found using sources of known sound power and the optimum microphone positions. The new method allows estimation of sound power of operational torque converters in a dynamometer test fixture.
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Citation
Reynolds, C., Blough, J., Anderson, C., Johnson, M. et al., "Sound Power Measurement in a Semi-Reverberant, Volume Deficient Chamber," SAE Technical Paper 2015-01-2359, 2015, https://doi.org/10.4271/2015-01-2359.Also In
References
- Alfayez , L. , Mba , D. , Dyson , G. The Application of Acoustic Emission for Detecting Incipient Cavitation and Best Efficiency Point of a 60 kW Centrifugal Pump: Case Study NDT & E International 38 5 354 358 2005
- ISO 3741:2012 Acoustics - Determination of sound power levels and sound energy levels of noise sources using sound pressure - Precision methods for reverberation test rooms
- ISO 3744:2012 Acoustics - Determination of sound power levels and sound energy levels of noise sources using sound pressure - Engineering methods for an essentially free field over a reflecting plane
- Kowalski , D. , Anderson , C. , and Blough , J. Cavitation Detection in Automotive Torque Converters Using Nearfield Acoustical Measurements SAE Technical Paper 2005-01-2516 2005 10.4271/2005-01-2516
- Lubman , David Precision of reverberant sound power measurements Acoustic Society of America 56 August 1974 523 533
- Robinette , D. , Anderson , C. , Blough , J. , Johnson , M. et al. Characterizing the Effect of Automotive Torque Converter Design Parameters on the Onset of Cavitation at Stall SAE Technical Paper 2007-01-2231 2007 10.4271/2007-01-2231
- Schlatter , William R. Sound power measurement in a semi confined space Master of Science Massachusetts Institute of Technology 1971 http://hdl.handle.net/1721.1/44687
- Strasberg , M. , Taylor , D. Propeller Cavitation Noise After 35 Years of Study Noise and Fluids Engineering 1977
- Walber , C. Torque converter turbine noise and cavitation noise over varying speed ratio PhD Dissertation Michigan Technological University 2012
- Zeng , L. , Anderson , C. , Sweger , P. O. , Narain , A. Experimental Investigation of Cavitation Signatures in an Automotive Torque Converter using a Microwave Telemetry Technique 9th ISORMAC 2002